Web tensioning device

ABSTRACT

The invention describes a device for winding up strips of photographic film after this latter has been cut longitudinally. The invention is characterized by a uniform distribution of the radial forces exerted upon the winding cores, so that each core is wound-up under conditions of uniform tension. The equal radial force is obtained by pressing air into axially situated flexible, elastic tubes, exerting a constant radial pressure upon brake shoes contacting carrier members for cores of spools onto which the film strips are wound.

United States Patent 1191 Smolderen et a1.

WEB TENSIONING DEVICE Inventors: Albert Emiel Smolderen, Aartselaar;

Joseph Marie Cappuyns, Berchem, both of Belgium AGFA-Gevaert N.V., Mortsel, Belgium Filed: Sept. 29, 1971 Appl. No.: 184,869

Assignee:

Foreign Application Priority Data Sept. 30, 1970 Great Britain 46547/70 US. Cl 242/56.9, 188/67, 188/365, 242/72 B Int. Cl B65h 19/04, B65h 75/18 Field of Search... 242/56.9, 75.2, 72 B, 147 A,

242/l56.2, 156, 67.1 R, 67.3 R; 188/67, 365

References Cited UNITED STATES PATENTS 1/1951 WeilandQ 188/365 4/1955 Collard 2 12/72 Primary Examiner-John W. Huckert Assistant ExaminerEdward J. McCarthy Attorney, Agent, or Firm-William J. Daniel [57] ABSTRACT The invention describes a device for winding up strips of photographic film after this latter has been cut longitudinally. The invention is characterized by a uniform distribution of the radial forces exerted upon the winding cores, so that each core is wound-up under conditions of uniform tension. The equal radial force is obtained by pressing air into axially situated flexible, elastic tubes, exerting a constant radial pressure upon brake shoes contacting carrier members for cores of spools onto which the film strips are wound.

6 Claims, 5 Drawing Figures PATENTEMI 18 an SHEET 1 [IF 4 1 WEB TENSIONING DEVICE This invention relates to a torque transmitting device.

The invention is particularly intended for embodiment in web tensioning devices with a friction coupling for applying a controlled and almost constant tension to a moving web.

A web tensioning device is disclosed in U.S. Pat. No. 2,961,183 of B. F. Herr, issued Nov. 22, I960, comprising a frictional brake ring which is urged axially against a tensioning roll extremity by a flexible rubber annulus which is fed with pressurised air.

When winding webs or strips, e.g., when winding strips separated from a web by longitudinally cutting this web at spaced positions, it is often necessary to wind up the strips with uniform tension. The use of an axial friction coupling according to said U.S. Patent is not satisfactory for this purpose. Due to a non-uniform distribution of the frictional forces on the various friction rings and to flexure of the shaft, the different strips will not be wound under the same tension.

According to the invention a device is provided for transferring the same torque from a shaft core to a number of carrier members, e.g., cylinders journalled on the shaft core in axially spaced relation,.wherein at the height of each carrier member at least one friction element is present which is capable of moving in radial direction under the influence of a member in response of a fluid under pressure and which cannot move in tangential direction with respect to the shaft, said friction element has a frictional face at its exterior side, said frictional face being capable of engaging an interior frictional surface of the said carrier members.

According to preferred embodiments of the invention it comprises torque transmitting mechanism comprising a shaft, brake shoes rotatable with said shaft and means responsive to fluid pressure for displacing said brake shoes radially outwardly with respect to said shaft and into frictional driving engagement with a plurality of annular members which encircle such shaft and are freely rotatable relative thereto.

The said annular members can directly or indirectly serve for the winding of separate strips or webs about the shaft. Preferably each of the annular members serves as driving member for a core or spool onto which a strip or web can be wound, the annular member having friction or other means which engages a said core orspool when the annular member is itself driven by the shaft. The coupling between each annular member and the corresponding strip or web core or spool is preferably such that the latter can easily be removed along the shaft when the coupling is released.

A suitable form of coupling which comes into effect when the annular member is driven by the shaft is a cam-lock type of coupling comprising cam faces on the annular memberand locking rollers or other elements which are interposed between such cam faces and the interior of the core or spool. When the annular member is driven, the cam faces cause the said locking elements to be displaced outwardly so that they become wedged between the annular member and the core or spool. When the annular member is turned in reverse, the core or spool becomes unlocked.

The radial movement of the brake shoes is preferably under the control of one or more inflatable or expansible members disposed between the shaft and such shoes. For example, there may be one or more inflatable tubes which are so disposed, and means for supplying gas underpressure to such tube(s). Preferably the fluid pressure is the same for the brake shoes of both or all of the annular members.

Preferably there is a said inflatable or expansible member, or two or more such members, which is or are common to the two or more annular members to be driven, so that the frictional forces driving said annular members are the same.

Mechanism according to the present invention can also be used for unwinding a number of material strips at the same tension.

The invention will be described by way of example with reference to the accompanying diagrammatic drawings, in which:

FIG. 1 is an elevation of an apparatus comprising a web-cutting device and wherein an embodiment of the present invention is applied for the winding up of the separated web strips;

FIG. 2 is a plan view of the apparatus according to FIG. 1;

FIG. 3 is a cross-sectional view of the torque transmitting mechanism on line 3-3 in FIG. 5;

FIG. 4 is a cross-section of the right hand side of the mechanism on line 4-4 of FIG. 3; and

FIG. 5 shows a cross-section of the left hand side of the mechanism on line 5-5 of FIG. 3.

The device for longitudinally cutting a material web 10 according to FIG. 1 comprises a web feeding spool 11, a holder 12 with knives for longitudinally cutting the web 10, a guide roller 13 and two strip winders 14 and 15 according to the invention.

The device of FIG. 1 is shown in plan view in FIG. 2 wherein the material web 10 is cut into seven strips numbered from 1 to 7. The odd strips are wound on the winding up cores l6 fitted to the rollers 15 whereas the even strips are wound on the winding up cores 16 of the roller 14. The longitudinal cutting device according to FIGS. 1 and 2 is operated as follows.

By means of knives mounted in the holder 12, the web 10 taken off the spool 11 is cut into seven strips, each of which is wound on a separate winding up core 16. The torque at which the cores are driven, is identical for all cores notwithstanding unequal stretch or faults which may be present in one strip or other.

One of the strip winders is illustrated in crosssectional view in FIG. 3. The winder comprises a driven shaft 20 with four grooves 21 extending over a greater part of its length. Air-tight and flexible hoses 22 to 25 are fitted in these grooves. For the sake of clarity the hose 22 is drawn in deflated position and the hoses 23, 24 and 25 are shown inflated. At the locus of the hoses 22 to 25 there are four brake shoes 26, 27, 28, 29 respectively, the angular position of which is secured by the bolts 36. These brake shoes are encircled by a discontinuous ring 30 of spring steel wire of approximately 1.5 mm in diameter. The brake shoes are thus radially outwardly displaceable under fluid pressure within the hoses 22-25. The outer faces of the brake shoes 26, 27, 28 and 29 are covered with Teflon (Registered Trade Mark) or some other material 37 providing the desired coefficient of friction.

Around the brake shoes there is a carrier member in the form of an annular member 31 with an interior frictional surface 32 and carrying cam faces 63. The annu- .lar member 31 is formed with a series of peripheral recesses in which a set of rollers 45 movable with the annular member, are accommodated. The bottom faces 60 of the recesses are raked so that when the annular member is driven from the shaft by the frictional contact of the brake shoes 26-29 with said annular member, in the sense indicated by the arrow 61, the rollers 45 are forced into engagement with the inner surface of the core 16 surrounding the annular member 31. Distance spindles 44 provide for an adequate parallelism between bearing rings 33 (shown on FIGS. 4-5) in which the rollers 45 are housed. The bolts 38 secure the coupling between said bearing rings 33 and said annular member 31 (see FIGS. 4-5).

The torque at which the annular member 31 is driven depends on the frictional engagement between the brake shoes 26-29 and the annular member 31 and this torque can therefore be adjusted by controlling the pressurised air in the hoses 22 to 25.

It will be seen from FIGS. 4 and 5 that there are several annular members such as 31 surrounding the shaft 20, each annular member being associated with a set of brake shoes as above described. Moreover, the different sets of brake shoes are displaceable by pressure in one and the same set of hoses 22-25 which extend along substantially the full length of the shaft. Each annular member is surrounded by a core such as 16 but only one such core is shown in FlGS. 4-5. It will be apparent that in operation, the driving torque will be the same for all cores 16.

It will be seen from FIG. 4 that the left hand ends of the hoses 22 to 25 are clamped tightly closed by means of a clamping ring 40, said clamping ring being fixed on the shaft 20 by means of a headpiece 39. At the opposite sides of the sets of brake shoes there are dust rings 41. Each annular member 31 is carried by means of slide bearings comprising steel rings 42 secured to shaft 20 and rings 43 made of Teflon (Trade Mark) with molybdenium disulphide secured to the annular member. Ball bearings could, of course, be used instead of slide bearings.

Each annular member 31 bears two rings 33 which are interconnected by means of two distance spindles 44. The corresponding set of rollers 45 are freely journalled in these rings 33. Said rings 33, rollers 45 and distance spindles 44 are held together by means of an enclosing ring 46. Foregoing parts are axially joined to the annular member 31 by means of bolts 38. For the sake of clarity the right part of the mechanism according to FIG. 4 has been rotated downwards over about to illustrate the role of said bolts 38. A ribbon of spring-steel 47 exerts a slight radial pressure on the rollers in order to secure an elastic contact with a core 16 and to prevent said rollers to slip completely into the deepest'point of the raked peripheral recesses.

FIG. 5 shows mainly the pressurized air supplying system necessary to expand the flexible hoses 22 to 25. Said system consists of a clamping ring 50 which tightly closes the ends of said flexible hoses. The air distributing ring 53 is clamped on the shaft and on head piece 62, both welded together, and embraces partially the air feeding ring 54 which is rotatable around said air distributing ring. An air-tight sealing is secured by a pair of sealing rings 55. An axial shifting of the different parts mounted on the shaft 20 is prevented by the 6 ring 48 and the bolts 49.

The pressurized air is supplied through valves 56 in the air feeding ring 54 and streams through the channel 4 57 towards the air distributing ring 53 in which passages 51 are drilled and sealed, if necessary, by means of the bolts 58. The air is further fed to the damping ring 50 in which inlet openings 52 are provided. Said openings are air tightly sealed with the help of the cover 59.

A winder constructed as described above operates in the following manner: The cores 16 are inserted on the winder shaft 20 over their respective carrier members 31 and pressurized air is supplied to the flexible hoses 21 to 25 through valves 56, the air feeding ring 54 and channel 57 towards the passages 51 of air distributing ring 53. From ring 54 the pressurized air passes to the clamping ring 50 which is provided with channels 52 connected to the flexible hoses 21 to 25 so that the latter start expanding. This expansion causes the brake shoes 26 to 29 to be shifted in radial direction until their frictional surface contacts the frictional surface 32 of the annular member 31. The latter carries the cam surfaces 63 which, upon rotation of shaft 20, engage the locking rollers 45 which are housed with their extremities in two rings, and yieldingly urge these rollers against the internal surface of the core 16. Depending upon the final pressure in the flexible hoses 21 to 25, the pressure between the frictional surfaces of the brake shoes 26 to 29 and the frictional surface 32 may be regulated. In doing so, the torque is automatically defined and, by keeping the pressure to a constant value, the torque will stay at a value proportional to said pressure. As the flexible hoses 21 to 25 extend over the full length of the shaft, each core will be driven with the same torque, permitting a reproducible strip take-up action. The device may be completed with air pressure regulating means and may be adapted to work automatically.

We claim:

1. A winding device for winding a plurality of web strips under uniform torque onto acorresponding plurality of cores arranged along the length of said winding device in axially spaced relation, said winding device comprising:

a rotatable driving shaft common to all said cores,

a plurality of annular carrier members rotatably mounted on said rotatable shaft, one for each core, said carrier members being arranged on said shaft in axially fixed determined positions, means providing a driving connection between each core and the corresponding carrier member, and

means for establishing a friction coupling between said rotatable shaft and said carrier members,

said last means comprising at least one inflatable member extending axially of the shaft in a position between the shaft and the plural carrier members, and means for inflating said inflatable member under pressure into engagement with both said shaft and plural carrier member to frictionally secure the same together, whereby said carrier members are driven by said shaft at uniform torque, said driving connection between each carrier member and the associated core being a one-way clutch means restraining said core against rotation relative to the carrier member in a direction opposite to the winding direction thereof.

2. A winding device according to claim 1 wherein said inflatable member comprises a flexible tube housed in a groove extending in the exterior surface over the full length of said rotatable shaft.

there are four of said grooves arranged at equi-spaced intervals around the shaft periphery, each housing a flexible tube.

5. A winding device according to claim 1 in which said one-way clutch means is of the cam-lock type comprising circumferentially extending cam surfaces at spaced peripheral intervals on the annular members and rotatable locking members which are interposed between such cam surfaces and the interior of the core.

6. A winding device according to claim 5 including retaining means for yieldingly retaining said locking members in place on each annular member. 

1. A winding device for winding a plurality of web strips under uniform torque onto a corresponding plurality of cores arranged along the length of said winding device in axially spaced relation, said winding device comprising: a rotatable driving shaft common to all said cores, a plurality of annular carrier members rotatably mounted on said rotatable shaft, one for each core, said carrier members being arranged on said shaft in axially fixed determined positions, means providing a driving connection between each core and the corresponding carrier member, and means for establishing a friction coupling between said rotatable shaft and said carrier members, said last means comprising at least one inflatable member extending axially of the shaft in a position between the shaft and the plural carrier members, and means for inflating said inflatable member under pressure into engagement with both said shaft and plural carrier member to frictionally secure the same together, whereby said carrier members are driven by said shaft at uniform torque, said driving connection between each carrier member and the associated core being a one-way clutch means restraining said core against rotation relative to the carrier member in a direction opposite to the winding direction thereof.
 2. A winding device according to claim 1 wherein said inflatable member comprises a flexible tube housed in a groove extending in the exterior surface over the full length of said rotatable shaft.
 3. A winding device according to claim 1 including a shoe surfaced with friction material disposed intermediate each such inflatable member and the inner surfaces of said plural carrier members, said shoe being mounted for radial displacement but restrained against peripheral movement relative to said shaft.
 4. A winding device according to claim 2 in which there are four of said grooves arranged at equi-spaced intervals around the shaft periphery, each housing a flexible tube.
 5. A winding device according to claim 1 in which said one-way clutch means is of the cam-lock type comprising circumferentially extending cam surfaces at spaced peripheral intervals on the annular members and rotatable locking members which are interposed between such cam surfaces and the interior of the core.
 6. A winding device according to claim 5 including retaining means for yieldingly retaining said locking members in place on each annular member. 